1. Field of the Invention
This invention relates to an outdoor entry to a building. More particularly, the present invention relates to a lift-assisted entrance covering an entryway to that portion of a building that is located below ground level. Yet more particularly, the invention relates to a lift-assisted entrance that provides easy, simple access to the below-ground-level entryway to a building. Still more particularly, the present invention relates to such a lift-assisted entrance that is constructed from lightweight, durable materials. Finally, the present invention relates to such a lift-assisted entrance that is functionally and architecturally compatible with the design of the above-ground portion of the building to which it is attached.
2. Description of the Prior Art
It is not uncommon for building to have a level--such as a basement or cellar--situated below the level or grade, of the ground surrounding the structure. Residential buildings in particular are constructed such that the principal living space is located above ground, while the basement is almost entirely underground. Access to the basement--or subterranean level--is often gained through the interior of the building, usually by way of a stairway.
It is frequently desirable, however, to have access to the basement level of a building directly from the outdoors. For example, the basement commonly serves as a storage area for various types of goods and equipment--including lawn furniture and gardening tools--designed for outdoor use, or for other bulky items. Frequently, such cumbersome items may not be easily removed from storage via an interior access-way. A basement entryway is typically constructed to provide access to the basement level from the outdoors by putting a doorway in the outer concrete or masonry wall of the basement and constructing foundation walls on the outside of the basement doorway. The foundation walls extend from below the floor level of the basement doorway up to slightly above ground level and create a space in which to construct a stairway that descends from the top of the foundation wall opposite the basement doorway down to the floor level of the basement doorway. Unless protected by an external structure, this access to the basement entryway, however, can result in serious damage to the overall building by exposing the basement to the elements, particularly water. In colder climates, it is also desirable to keep the steps of such an entryway dear from any ice or snow that may accumulate and pose a hazard to a person attempting to use the outdoor stairway. Furthermore, it is desirable to prevent unauthorized access to the building by animals and human intruders through such an outdoor entryway. Typically, a bulkhead is installed above the basement entryway. These assemblies have numerous other names, such as cellar doors, cellar hatchway doors, basement doors, or hatches. For the sake of simplicity, I shall refer to the external protective door assembly of the prior art that is installed above a basement entryway as a bulkhead.
The ubiquitous BILCO BASEMENT DOOR of The Bilco Co. is a well-known bulkhead that is typically installed above a basement entryway of a residential building. This bulkhead is very similar in design to the bulkhead disclosed by Lyons (U.S. Pat. No. 2,174,989; issued 1939). Both devices have a pair of doors mounted in a frame that is attached to an outer masonry or concrete wall of the main building and to a basement entryway foundation. The frame and the doors slope downward away from the main building to grade level and are generally made of heavy gauge sheet metal, although, in the past, some bulkheads of this design were made of wood. Being constructed of heavy gauge sheet metal, the doors of the Lyons device and the BILCO device are heavy and unwieldy. No means for assisting in the opening and lifting of the doors is provided. The absence of any such assisting mechanism exposes the user to unnecessary strain and to risk of injury. The user must bend down to grasp the door handle, which is just a few inches above grade, and pull up to lift the door. The typical weight for the two standard sizes of the BILCO installation, for example, is reported as 175 lbs. and 196 lbs. respectively. The weight of a single door panel to be lifted is approximately 44 lbs and 49 lbs, respectively. Lifting this weight from a bent over position puts an unhealthful strain on the lower back. Furthermore, if the door should suddenly drop down to a closed position, the potential for serious injury to a person standing in the entryway is great.
Several attempts have been made to overcome the problem of having to lift the entire weight of the door. Wyatt (U.S. Pat. No. 3,103,996; issued 1963) discloses a hatchway door that is similar in shape to the BILCO and Lyons devices, but employs binge and spring elements to bias doors toward an open position, thereby partially assisting the user in opening the doors. Sbepard et al. (U.S. Pat. No. 2,686,340; issued 1954) discloses a self-balancing hatchway door. This device includes a single, downwardly sloping door pivotally connected to tension springs that assist the user in both opening and closing the door, as well as in balancing the door in an intermediate position. All of these bulkheads, i.e., the bulkheads disclosed by BILCO, Lyons, Wyatt and Shepard et al., are constructed of heavy-gauge steel and are consequently very heavy. The weight of the door alone poses a safety risk to the user, even if some means of lift-assist are provided. An open door that weighs over 40 lbs. can cause considerable injury to a person should it suddenly drop shut, for example because the lift-assist means failed or was accidentally tripped to close, or because the door was blown shut by a sudden gust of wind.
Vardaro (U.S. Pat. No. 5,600,921; issued 1997) discloses a bulkhead that includes a downwardly sloping, single fiberglass door and pneumatic struts that assist the user in opening the door. The door is of necessity quite large and unwieldy, albeit lightweight. The Vardaro device, as well as the Shepard et al. device, both of them being designed with a single, flat door that opens upward, may obstruct head-room and force the user to duck when ascending from or descending into the stairway.
Beyond the structural shortcomings of each of the above-mentioned devices, the prior-art bulkheads serve a utilitarian function but are aesthetically displeasing and unsightly. Having an outer appearance consisting of typically a flat, downwardly-sloping sheet metal surface, no effort has been made to reconcile the utility of such devices with the overall architectural schemes of the buildings they serve.
Therefore, what is needed is an lift-assisted entrance that will protect a subterranean basement entryway from the elements of the weather when it is closed. What is further needed is such a lift-assisted entrance that will provide easy access to the subterranean basement entry. What is yet further needed is such a lift-assisted entrance that can be used without posing the risk of injury or strain to the user. Finally, what is needed is such a lift-assisted entrance that is architecturally compatible with the principal building to which it is attached.